Product Specs

PRELIMINARY PRODUCT SPECIFICATION
nRF24L01 Single Chip 2.4 GHz Radio Transceiver
Nordic Semiconductor ASA - Vestre Rosten 81, N-7075 Tiller, Norway - Phone [phone] - Fax [phone]
Page 29 of 38
Revision: 1.1
November 2005
PERIPHERAL RF INFORMATION
Antenna output
The ANT1 & ANT2 output pins provide a balanced RF output to the antenna. The
pins must have a DC path to VDD, either via a RF choke or via the center point in a
dipole antenna. A load of 100+j175 is recommended for maximum output power
(0dBm). Lower load impedance (for instance 50

) can be obtained by fitting a
simple matching network.
Output Power adjustment
SPI RF_SETUP
(RF_PWR)
RF output power
DC current
consumption
11
0 dBm
11.3 mA
10
-6 dBm
9.0 mA
01
-12 dBm
7.5 mA
00
-18 dBm
7.0 mA
Conditions: VDD = 3.0V, VSS = 0V, T
A
= 27ºC, Load impedance = 100+j175.
Table 14 RF output power setting for the nRF24L01.
Crystal Specification
Frequency accuracy includes initial accuracy (tolerance) and stability over
temperature and aging.
Frequency
C
L
ESR max
C
0max
Frequency accuracy
16MHz
12pF
 
7.0pF
±60ppm
Table 15 Crystal specification of the nRF24L01
To achieve a crystal oscillator solution with low power consumption and fast start-up
time, it is recommended to specify the crystal with a low value of crystal load
capacitance. Specifying C
L
=12pF is OK, but it is possible to use up to 16pF.
Specifying a lower value of crystal parallel equivalent capacitance, C
0
will also work,
but this can increase the price of the crystal itself. Typically C
0
=1.5pF at a crystal
specified for C
0max
=7.0pF.
nRF24L01 sharing crystal with a micro controller.
When using a micro controller to drive the crystal reference input XC1 of the
nRF24L01 transceiver some rules must be followed.
Crystal parameters:
When the micro controller drives the nRF24L01 clock input, the requirement of load
capacitance C
L
is set by the micro controller only. The frequency accuracy of ±60
ppm is still required to get a functional radio link. The nRF24L01 will load the crystal
by 0.5pF at XC1 in addition to the PBC routing.